The invention relates generally to pumps, and more particularly to a peristaltic pump wherein a plurality of rollers disposed on a rotor successively engage one or more lengths of tubing to effect pumping of fluid therethrough.
In recent years, peristaltic pumps have proven to be well suited for many applications involving pumping of various fluids in laboratory, medical, and other applications. A particular advantage of peristaltic pumps is their ability to pump fluids through a continuous, unbroken length of tubing, without the fluid in the tubing contacting any components of the pump other than the tubing itself.
In many contexts, it is desirable to change tubing frequently in a particular pump. Various efforts have been made to enable removal and insertion of tubing with relatively little time and effort. For example, U.S. Pat. No. 5,082,429 and U.S. Pat. No. 4,231,725 disclose peristaltic pumps having movable occlusion beds which can be shifted between a closed, or operating position, and an open, or loading/unloading position, to facilitate changing of tubing. Other peristaltic pumps are illustrated in U.S. Patent Nos. 4,256,442; 5,133,650; 3,963,023; 5,110,270; 4,886,431; and 5,147,312.
The provision of a mechanism for quickly and easily opening the pump to permit loading and unloading of tubing, and closing the pump to permit peristaltic pumping, requires that several considerations be addressed. Among these are the fact that in the closed position, the occlusion bed must be stably supported in a desired spatial relationship to the rotor, notwithstanding relatively high dynamic pumping forces directed radially outward against the occlusion bed during pumping. The locking mechanism must be capable of withstanding such forces and operational loads without loosening, without excessive vibration, and without displacement that would adversely affect the ability to maintain precise control of pump flow rates. Any increase in the distance between the occlusion bed and the rotor changes the occlusion of the tubing, and can result in unacceptable variations in flow rates. Another consideration is the need for the pump to be capable of economical manufacture. Economic considerations are particularly important in the health care industry, where peristaltic pumps serve various roles, from administration of intravenous fluids requiring intermittent pumping at low flow rates, to blood analysis and other laboratory work requiring pumping at higher flow rates. In developing peristaltic pumps for such applications, the need for precision and reliability is, of course, paramount.
Another consideration in the design of peristaltic pumps is size and weight. Particularly in applications where the pump is to be incorporated as a component of a larger analytical unit or other piece of equipment, a pump manufacturer may need to comply with exacting specifications as to maximum pump dimensions, and maximum pump weight, while also complying with performance specifications, including the capability to pump at specified flow rates within specified flow rate tolerances.
A general object of the invention is to provide a compact, lightweight peristaltic pump which is capable of pumping at relatively high flow rates with a high degree of reliability and precision, and which is capable of economical manufacture. A further object is to provide a peristaltic pump having means to facilitate loading and unloading of tubing.